This invention relates generally to the art of solar collectors, and more specifically concerns curved solar collectors which are made of glass.
If solar collectors are to become an economical source of power, they must not only be as efficient as possible, but they should also be resistant to weather damage and chemical degradation. They should furthermore be lightweight, inexpensive, and should have a low coefficient of expansion.
The configuration of a solar collector has a significant impact on efficiency, while the materials used in the construction of a solar collector significantly impact the other considerations. With respect to solar collector configuration, it is known that a parabolic shape is very efficient, while with respect to materials, plastic, aluminum and glass have been used. Glass has many characteristics which make it an especially good choice for use in solar collectors, inlcuding its good surface qualities, its high transmittance, its excellent chemical durability and its high resistance to ultraviolet. Also, glass is relatively inexpensive and is readily available.
Glass would thus be otherwise preferred were it not for several significant disadvantages. A first and primary disadvantage is that it has heretofore been very difficult to form glass into the desired shape with the degree of accuracy required. For instance, it is preferred that the curve of parabolic reflectors be accurate to within 1/10th of a degree. However, this degree of accuracy is currently not available.
Secondly, current processes require a considerable amount of handling, and cannot realistically be automated. Hence, the resulting product is rather expensive, even though the raw material is relatively inexpensive. Further, a crack in a glass reflector will usually propagate, even if the glass is bonded to a support surface, and hence, damage to such a reflector is most often not confined to just a local impact area.
Because of such disadvantages, glass has not been used extensively for curved collectors.
Accordingly, it is a general object of the present invention to provide a method for producing a product, and the product itself, which overcomes one or more of the disadvantages of the prior art noted above.
It is a further object of the present invention to provide such a method by which curved glass solar collectors can be produced inexpensively.
It is another object of the present invention to provide such a method by which a very accurate curved solar collector is produced.
It is an additional object of the present invention to provide such a product in which the effect of damage to the collector is confined to a localized area.
It is a still further object of the present invention to provide such a process which is capable of being automated into a continuous process.